The invention relates to a support member for supporting a mortar shell into a barrel of a breech-loading weapon. The support member comprises a support element including a rim flange and a firing mechanism for firing the actual primer of the mortar shell. The support member further includes means for attaching the support element to at least one guiding fin disposed at the tail of the mortar shell. The invention also relates to a method for attaching a support member to a mortar shell.
A mortar can be arranged on a movable base, such as an armored vehicle, allowing the mortar to be moved conveniently from one place to another and, on the other hand, allowing it to be rapidly moved from the emplacement into safety. When the intention is to use a mortar for firing vertically or downward, the problem is that the mortar shell does not stay in place in the smoothbore barrel of the mortar, but may slide forward in the barrel, so that it can no longer be fired. U.S. Pat. No. 5,503,080 discloses a support member attachable by means of friction to tail fins in the mortar shell. However, the friction joint taught by the publication does not achieve sufficiently reliable attachment of the support member. Furthermore, the dimensions of the support member and the tail fins show at least some deviations due to the manufacture, which cause variation in the magnitude of the attachment force.
The object of the present invention is to provide a new and improved support member for supporting a mortar shell into the barrel of a breech-loading weapon, and a method for attaching such a support member.
The support member of the invention is characterized in that the means for attaching the support element include at least one attachment piece; the attachment piece including at least one longitudinal shaft, the shaft being adaptable substantially longitudinally to the mortar shell, and a first end of the shaft being supportable to the support element; and a second end of the shaft of the attachment piece including a support portion transversal to the longitudinal axis of the mortar shell for supporting the attachment piece to the front surface of the guiding fin; and the attachment piece including at least one predetermined deformable point allowing a fired mortar shell to be detached from the support member.
The method of the invention is characterized by supporting the support member to the front surface of at least one guiding fin by means of at least one attachment piece arranged between the support element and said front surface.
The essential idea of the invention is to attach a support member, including a rim flange and a firing member, to the tail of the mortar shell. The front rims of the guiding fins at the tail of the mortar shell are utilized in attaching the support member. For the attachment, the support member is provided with at least one attachment piece including at least one shaft portion, longitudinal to the mortar shell, and a transverse support portion. Said support portion is arranged to settle against the front rim of the guiding fin. The attachment piece further includes at least one predetermined point arranged to deform during firing and thus to enable the detachment of the mortar shell from the support member.
In the invention, attaching the support member to the tail of the mortar shell is based on shape locking, the attachment being more reliable than attachment based on friction. Furthermore, possible dimensional variance due to the manufacture of the mortar shell does not affect the magnitude of the attachment forces and the fastening of the support member as critically as in a friction-locked solution. In the inventive solution, attachment forces are relatively easy to manage. A further advantage of the invention is that the support member is easily and rapidly attachable to the tail of the mortar shell even under difficult circumstances.
The essential idea of an embodiment of the invention is that the attachment piece is provided with a weakened point, which is arranged to break or bend when the mortar shell is fired. The weakening can be provided by arranging a portion having a smaller cross-section at the predetermined point. The weakening ensures that the attachment piece breaks or bends at the preplanned point, and that the deformation takes placed in a controlled manner and not until a higher force than the preplanned attachment force is directed to the attachment piece. This ensures that the attachment piece or its parts do not under any circumstances follow the fired mortar shell, and do consequently not damage the weapon or affect the aerodynamics of the mortar shell.
The essential idea of an embodiment of the invention is to arrange the attachment piece to form a loop around at least one guiding fin.
The essential idea of an embodiment of the invention is that the shaft and the support portion form a substantially T-shaped portion at the front end of the attachment piece. This allows the shaft to be arranged between two adjacent guiding fins, the transverse support portion being, in turn, supportable against the front rims of adjacent guiding fins.
The essential idea of an embodiment of the invention is that the support member includes a support ring to which the rear end of the attachment piece is supported, and the support ring can be pulled backward by means of the support element. In this case, the attachment piece can be tightened to the desired tightness between the guiding fin and the support ring.